Copilot said: Functional Neurological Disorder (FND) is a condition Functional Neurological Disorder (FND) is a condition in which patients experience neurological symptoms—such as weakness, movement disorders, sensory symptoms, or blackouts—that are genuine and disabling but are not caused by structural disease or damage to the nervous system. Instead, these symptoms are thought to arise from abnormal functioning of the nervous system, often related to problems with how the brain and body communicate, rather than from physical injury or illness.